Rolled tube fabrication method

ABSTRACT

A rolled tube fabrication method of making a rolled tube by: cutting a surface-treated metal sheet material subject to the desired size, and then bending the two opposite lateral side edges of the surface-treated metal sheet material into a respective hooked portion, and then forcing the two hooked portions of the surface-treated metal sheet material to hook each other, and then roller-ramming the hooked area of the surface-treated metal sheet material so as to obtain a finished rolled tube.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to the fabrication of rolled tubesand, more particularly, to a simple, economic rolled tube fabricationmethod, which eliminates the process of welding.

[0003] 2. Description of the Related Art

[0004] Conventionally, a rolled tube is made, as shown in FIGS. 1 and 2,by rolling up a metal sheet material A into a tubular shape, and thensealing the abutted edges of the tubular metal sheet material with awelding apparatus, and then adhering the surface of the tube with alayer of covering or spray-painting/electroplating the surface of thetube with a layer of coating. This rolled tube fabrication method hasnumerous drawbacks as follows:

[0005] 1. Due to complicated processing procedure, the manufacturingcost of this method is high.

[0006] 2. Because the abutted edges of the tubular metal sheet materialare welded together, the welded area must be cleaned or polished beforethe covering layer bonding, spray-painting or electroplating process,and the roundness control of the tube is difficult to maintain.

[0007] 3. The surface treatment can only be employed to the outersurface of the tube, and the inner surface of the tube cannot be welltreated with a surface treatment.

[0008] 4. Because a welding process is necessary, the selected metalsheet material must have a certain wall thickness. If a thin metal sheetmaterial is used, the flame of the welding apparatus used may cutthrough the wall of the metal sheet material during welding. Further,when a thin metal sheet material is used and rolled into a tube, therolled tube can easily be deformed.

SUMMARY OF THE INVENTION

[0009] The present invention has been accomplished under thecircumstances in view. It is the main object of the present invention toprovide a rolled tube fabrication method, which eliminates the aforesaiddrawbacks. It is another object of the present invention to provide arolled tube fabrication method, which is practical and economic formaking rolled tubes for use in blind fabrication. According to oneaspect of the present invention, a surface-treated metal sheet materialis used and cut subject to the desired size, and then the two distalside edges of the surface-treated metal sheet material are bent into arespective hooked portion, and then the two hooked portions of thesurface-treated metal sheet material are respectively coated with alayer of glue and then hooked up, and then the hooked area of thesurface-treated metal sheet material is roller-rammed, and thus afinished rolled tube is obtained. According to another aspect of thepresent invention, a bonding agent is applied to gaps in the hooked areabefore roller ramming. According to still another aspect of the presentinvention, the roller-rammed area of the rolled tube forms a rib thatenhances the structural strength of the rolled tube.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a cross-sectional view of a rolled tube made accordingto the prior art.

[0011]FIG. 2 is a block diagram showing a rolled tube fabrication flowaccording to the prior art.

[0012]FIG. 3 is a cross-sectional view, hooked portions of the metalsheet material hooked together according to the present invention.

[0013]FIG. 4 is a block diagram showing a rolled tube fabrication flowaccording to the present invention.

[0014]FIG. 5A is a cross-sectional view of a finished rolled tube madeaccording to the present invention.

[0015]FIG. 5B is an enlarged view of a part of FIG. 5A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] Referring to FIGS. 3, 4, 5A and 5B, a metal sheet material 10 isselected, and then a surface treatment is employed to the metal sheetmaterial 10. The surface treatment can be any of a variety ofconventional methods. For example, the two sides of the selected metalsheet material can be respectively bonded with a respective layer ofcovering material, spray-painted with a respective layer of coating, orelectroplated. The surface treated metal sheet material is then cutsubject to the desired size, and then the two distal side edges of thesurface treated metal sheet material are respectively turned downwardsand then backwards, or upwards and then backwards, forming a respectivehooked portion, and then the hooked portions are respectively coatedwith a layer of glue, and then the surface treated metal sheet materialis rolled into the shape of a tube for enabling the two hooked portionsto be hooked together. Thus, a semi-finished tube is obtained (see FIG.3). Thereafter, the connected hooked portions of the semi-finished tubeare roller-rammed into a flat structure (see FIGS. 5A and 5B).

[0017] While only one embodiment of the present invention has been shownand described, it will be understood that various modifications could bemade thereunto without departing from the spirit and scope of theinvention disclosed.

What the invention claimed is:
 1. A rolled tube fabrication methodcomprising the steps of a) selecting a surface-treated metal sheetmaterial and cutting the selected surface-treated metal sheet materialsubject to a predetermined size; b) bending the selected surface-treatedmetal sheet material to form two hooked portions at two opposite lateralsides of the selected surface-treated metal sheet material; c) forcingthe hooked portions of the selected surface-treated metal sheet materialto hook up each other; and d) roller-ramming the hooked area of thehooked portions of the selected surface-treated metal sheet material. 2.The rolled tube fabrication method as claimed in claim 1, furthercomprising a sub-step of covering said hooked portions with a layer ofglue before forcing said hooked portions to hook up each other.